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VAS continued…

Each process allocate VAS in the starting. As required, the VAS regions will be bind to the physical memory. This will be done by means of committing(using VirtualAlloc API), AWE mechanism, file mapping API’s etc.

Physical pages can be shared or private. If the same physical pages are shared accross different VAS, its called shared physical pages, else if only mapped to a single VAS, they are called private physical pages. The physical pages could be either in disk or ram. If its only from RAM, its referenced as working set or memory usage in windows task manager.

Working set shown in the perfrmon & task manger includes non private pages.

Working Set in Perfmon counter = Mem Usage in Task manager
Private Bytes in perfmon counter = Virtual Memory Size in Task Manager